A smoky fire at Macy’s flagship store in Herald Square this afternoon sent shoppers fleeing from the department store, authorities said.

The all-hands blaze broke out in the basement at about 3:30 p.m. and sent smoke wafting through the building, fire officials said.

Shoppers were evacuated as 65 firefighters battled to knock it down.

It’s not immediately clear what sparked the fire.

The store was temporarily closed.

In a statement, Macy’s called the incident “a minor fire.”

“All customers and store employees were evacuated immediately and safely,” the store said. “FDNY responded immediately and is continuing its investigation. No one was hurt and we received the all clear from the FDNY to re-open the store.”